Glider press

ABSTRACT

A stencil screen printing press is illustrated having a peeling means which elevates the screen from the surface being printed immediately behind the squeegee for &#39;&#39;&#39;&#39;off-contact&#39;&#39;&#39;&#39; printing. The peeling means elevates the screen faster when the squeegee is at the center of the screen than when the squeegee is at either end to compensate for stretching of the fabric. A novel registration means operating in conjunction with the peeling means is also illustrated. A simplified mechanical drive arrangement permits the press to be of universal design, allowing it to be scaled up or down in width and length to any desired size. A novel carriage assembly to support the squeegee and flood bar is also shown, having a captivated cam arrangement which shifts the squeegee and flood bar at the end of the stroke. Quick change from flood to non-flood condition is also provided.

[ 51 May 8, 1973 [54] GLIDER PRESS [75] Inventors: Henry J. Bubley,Deerfield; Claude 11. Ohm, Chicago, both of 111.

[73] Assignee: American Screen Process Equipment Company, Chicago, Ill.

[22] Filed: Oct. 26, 1970 [21] Appl. No.: 83,800

[52] US. Cl. ..101/114, 101/123 [51] Int. Cl. ..B4li 15/00 [58] Field ofSearch ..101/114, 121-124,

[56] References Cited UNITED STATES PATENTS 1,102,884 7/1914 Delevil..101/114 1,898,406 2/1933 Tate et al.. ..l0l/l23 2,018,989 10/1935 Wulf..101/123 X 2,581,775 l/l952 Wade ..101/123 2,704,510 3/1955 Walsh,Jr... ..101/126 X 2,936,705 5/1960 I-Iall ..101/123 2,963,964 12/1960Klump... ..101/126 X 2,975,705 3/1961 Gilman...... ..101/123 3,101,6658/1963 Hall ..101/123 3,166,011 1/1965 Landesman.. ..l0l/l23 3,263,6038/1966 Fuchs ..101/123 FOREIGN PATENTS OR APPLICATIONS 702,297 3/1966Italy ..101/123 702,298 3/1966 Italy ..101/123 1,207,836 2/1960 France..lOl/123 Primary Examiner-Robert E. Pulfrey Assistant Examiner-Eugenel-I. Eickholt Attorney-Robert E. Wagner 5 7 ABSTRACT A stencil screenprinting press is illustrated having a peeling means which elevates thescreen from the surface being printed immediately behind the squeegeefor off-contact printing. The peeling means elevates the screen fasterwhen the squeegee is at the center of the screen than when the squeegeeis at either end to compensate for stretching of the fabric. A novelregistration means operating in conjunction with the peeling means isalso illustrated. A simplified mechanical drive arrangement permits thepress to be of universal design, allowing it to be scaled up or down inwidth and length to any desired size. A novel carriage assembly tosupport the squeegee and flood bar is also shown, having a captivatedcam arrangement which shifts the squeegee and flood bar at the end ofthe stroke. Quick change from flood to non-flood condition is alsoprovided.

20 Claims, 13 Drawing Figures PATENTEURAY' 81m 3.731.623

SHEET 1 OF 4 INVENTORS HENRY J. BUBLEY CLAUDE H. OLTRA BY ATT'YPATENTEDHAY' 8191s SHEET 2 OF 4 I INVENTORS HENRY J. BUBLEY CLAUDE H.OLTRA W ATT'Y.

PATENTEDHAY 8W 3.731.623

SHEU H []F 4 ll'lh IN VENTORS HENRY J. BUBLEY CL AUDE H OLTRA ATT'Y.

GLIDER PRESS This invention relates to stencil screen printing apparatusin general and, more specifically, to a new and improved stencil screenprinter having various novel features which improve its performance andpromote economy in manufacture.

In known types of stencil screen printing apparatus, the screen frame israised and lowered to permit insertion and removal of the stock to beprinted. In many instances, this may be a paper sheet, piece ofhardboard, plywood or the like. When the stencil screen is in thelowered position, a squeegee is pushed over the stencil screen to forceink through the screen and onto the sheet to print the intelligencepattern formed on the screen. After the print stroke, the squeegee israised and a flood bar is lowered into engagement with the screen topush the ink across the screen to the starting point of the printstroke. During the return, the screen is in the elevated condition topermit the printed stock to be removed and an unprinted piece inserted.

In some printing techniques, the flood bar and squeegee cooperate witheach other in a non-flood" condition to form a carrier to carry the inkpool to the starting point of the printing stroke where the squeegeealone will force it through the stencil screen to perform the printingfunction.

It is highly desirable, especially inthe larger screen sizes, to havethe screen elevated or peeled away from the work immediately behind thesqueegee without permanently distorting the screen in order to obtainthe sharpest print. This is referred to in the trade as offcontactprinting. In the past, this has been accomplished through a springmechanism which exerted a constant upward force on the chase or screenframe with some means such as a roller or the like acting in oppositionon the chase or screen frame to positively hold the screen frame in thedown position. The roller moved along with the squeegee, permitting thescreen to be elevated at a uniform rate. This technique left somethingto be desired when consideration is given to the fidelity of theresulting print.

It has now been found that the best results in off-contact printing canbe obtained by having the peeling mechanism positively actuated withresistance to the elevating force supplied solely by the squeegee.Through the novel peeling mechanism of the present invention, the rateof peeling follows a harmonic motion pattern in that it peels faster atthe center of the screen that at either end, thereby compensating forthe natural tendency of the screen material to stretch. This assuresthat the print will be sharp in all areas printed.

A novel carriage assembly is provided having a novel shuttle mechanismwith captivated cams to shift the squeegee and flood bar from the printcondition to the flood condition on the return stroke. The carriageassembly also includes a novel change-over arrangement which permits therapid conversion from the conventional flood bar arrangement to anon-flood scoop. This is accomplished by shifting a pivot pin in each ofthe carriage assemblies and substituting a non-flood scoop for a floodbar. t i

The present invention is a simplified design providing a noveladjustment which allows the print stroke to be varied, The print strokeis always initiated at the front of the press and the length of strokedetermined by a simple adjustment on the drive mechanism. Moreover, inconjunction with the novel peeling means described above, a unique guideis provided which assures accurate registration on each printing strokeeven in offcontact printing.

Because of the simplicity of the novel design, the press may be scaledup or down, depending upon requirements, with the general basic designused for both large and small press sizes. Only the strength of thematerials utilized limits the maximum size of the press. This feature isderived as a result of the location of the drive arms outside the driveframe but inside the chase and bed. The unique drive arrangement is alsolocated so that the bed and chase on any given press may be scaled up ordown since there is nothing to prevent either from being increased ordecreased in over-all size. Moreover, the underside of the bed is freeof obstruction, permitting the use of mechanical-type feeds such as avacuum belt feed and takeoff as is described in co-pending applicationSer. No. 49,828, filed June 25, 1970 and entitled Vacuum Belt". Otheradvantages of the novel press design will become apparent uponconsideration of the objects and following description.

It is a principal object of this invention to provide a new and improvedprinting press of the stencil screen type.

It is a further object of this invention to provide a new and improvedprinting press having a novel peeling means which elevates the screenfrom the surface being printed immediately behind the squeegee.

It is a still further object of this invention to provide a stencilscreen printing press having a novel peeling means which peels at afaster rate at the center of the screen than at either the forward orrearward ends.

It is a still further object of this invention to provide a new andimproved stencil screen printing press having a novel peeling means andguide means which functions to assure accurate registration.

It is a still further object of this invention to provide a stencilscreen printing press of uncomplicated design having a novel drivearrangement permitting the press to be manufactured in various sizesthrough merely increasing the size of the components.

It is a still further object of this invention to provide a stencilscreen printing press having novel carriage assemblies supporting thesqueegee and flood bar, said carriage assemblies including a uniqueshuttle arrangement which permits the rapid conversion from flood tonon-flood.

It is a still further object of this invention to provide a stencilscreen printing press including un'ique carriage assemblies to supportthe squeegee and flood bar, which carriage assemblies include captivatedcams to shift the flood bar and squeegee in timed relation to the pressmovement.

Other objects and advantages of the present invention will becomeapparent upon consideration of the accompanying drawings and attendantdescription.

IN THE DRAWINGS FIG. 1 is a perspective view of the printing press ofthe present invention;

FIG. 2 is an enlarged fragmentary side elevation of the printing pressshown in FIG. 1 with the screen in the lowered or printing position;

FIG. 3 is a front elevational view of the press shown in FIG. 2 with thecarriage assembly omitted for clarity and parts broken away to show theregistration pins;

FIG. 4 is a schematic side elevational view of the press shown in FIGS.1-3 with dotted lines to show the position of the drive arms at the endof the printing stroke;

FIGS. 5A, 5B and 5C are schematic side elevational views to illustratethe operation of the novel peeling arrangement in relation to squeegeemovement during off-contact printing;

FIG. 6 is a rear elevational view of the press shown in FIGS. 1-4 withthe screen in the down or print position;

FIG. 7 is a top plan view of the squeegee and flood bar carriageassembly with the support arms shown fragmentarily;

FIG. 8 is a side elevational view of the carriage assembly taken alongthe line 8-8 of FIG. 7 with the squeegee and flood bar in the conditionassumed during the printing stroke;

FIG. 9 is a view similar to FIG. 8 with the carriage assembly in theposition assumed on the return stroke;

FIG. 10 is a view similar to FIG. 9 with a non-flood scoop attached andthe carriage assembly converted to the non-flood scoop condition; and

FIG. 11 is a graph to illustrate the rate of elevation of the screen ofthe present invention contrasted with one of known prior art type.

Referring now to FIG. 1, reference character 10 generally indicates theimproved press of the present invention. The press 10 includes a frame11 having an operating console 12 located at the lower front whichpermits the operator to control the operation of the press. A drivehousing 13 is disposed at the rear of the frame 11 and houses the motorand drive elements which will be described in greater detail hereinafterwith respect to FIG. 6.

A printing bed 14 is.located on the top of the frame 11 and may be ofany suitable type with or without vacuum means to hold the stock to beprinted during the printing operation. In the preferred form of theinvention, the bed 14 consists of a vacuum base of the type described inUS. Pat. No. 3,429,544 to Williams, issued Feb. 25, 1969 for AIR TABLE.Vacuum to the base is supplied through a flexible tube l5joined to avacuum source indicated generally at 16 and supported on the frame 11 inthe drive housing 13. The air flow through the tube may be reversed toprovide a blow-back release of the stock being printedv Because of theunique drive arrangement, this sequence is easily selected or modified.

A screen press printing head is indicated generally at 20 and isdisposed for pivoting movement away from and toward the press bed 14 ina manner well known. When the printing head 20 is in the condition shownin FIG. 1, the stock previously printed may be removed and unprintedstock inserted. Such stock may be ofany desired type such as paper,cardboard, hardboard, plywood, cloth or the like.

A pair of arms 21 and 22 serve to support a screen assembly indicatedgenerally at 23. The screen assembly 23 consists ofa master frame orchase 24 which serves to mount a stencil screen 25 of known type. Thestencil screen consists of frame and screen fabric which may be formedof polyester, nylon, stainless steel or the like. The stencil screen 25is held in the chase 24 by clamps 26 or the equivalent acting againstits frame. These are chosen to facilitate ease in replacement of thescreen.

As seen in FIG. 2, the master chase 24 is pivoted as indicated at 27 topermit movement relative to arms 22 and 23. The chase 24 is supportedbeneath arms 22 and 23 for movement relative to the arms in a manner tobe described hereinafter.

The arms 22 and 23 are formed from box-like or hollow members which aresupported at the rear of the press for pivoting movement on oppositeends of a shaft 28 received in bearings 30 and 31 on opposite sides ofthe frame. A transverse brace 32 also connects the arms at theirrearward portions to provide the requisite rigidity. At the forward endof the arms are provided vertical braces 33 and 34 which are joined attheir lower ends by a transverse brace or head tie bar 35 to providelateral rigidity.

As best seen in FIG. 3, the head tie bar 35 has a vertical guide 36attached for positioning between pairs of rollers 37 and 38 which aremounted on the master chase. This assures that the chase will be guidedin its vertical movement during the peeling operation which will bedescribed in greater detail hereinafter.

As seen in the right-hand portion of FIG. 3, at the lower end of thebrace 33 is a frusto conical opening 18 to receive the frusto conicalpin 19 carried on the frame 11. A similar pin 19' is received in thebrace 32. This assures that the forward part of the arms 22 and 23 willbe properly positioned before the printing stroke commences and willmaintain registration throughout the stroke.

Disposed on each of the arms 22 and 23 is a carriage assembly of thetype shown at 40 in FIG. 2 and 41 in FIG. 7. The carriage assemblies 40and 41 are of identical but reverse construction, one being a mirrorimage of the other. In the interest of brevity, specific descriptionwill be limited to the carriage assembly 41 which is mounted on the arm23 and shown in greater detail in FIGS. 7-10.

In FIGS. 7-10, the carriage assembly 41 is illustrated in various modesof operation. As can be seen, the carriage assembly 41 is carried on thearms 23 and includes a housing 42 which has a U-shaped portion closedoff by a side plate 43 bolted or attached by equivalent means to theU-shaped portion. Nylon pads or guides (not shown) are provided withinthe housing 42 to assure smooth and friction-free movement of thecarriage along the arm 23 although lateral forces are minimal inoperation. A brake pad 160 of nylon or the equivalent is located betweenthe top of the respective arm and housing supporting the ends of thesqueegee. A set screw 161 permits adjustment of the spring force appliedto the pad 160 to whatever degree is desired. A. pair of rods 44 and 45join the carriage assemblies 40 and 41 to assure unitary movement.

Ashuttle 46 is interposed between the side plate 43 and the outersurface of the arm 23. The shuttle 46 is held captive in the carriagehousing 42 and is provided with a pair of oppositely-directed cam tracks50 and 51 which are mirror images of each other and function to shiftthe flood bar and squeegee, respectively. Due to the resistance tomovement by the brake pad 160, the shuttle is assured of being actuatedwith each change in direction of movement.

On the outside of the housing 42 is a scissors-type squeegee and floodbar support which includes a squeegee supporting lever 52 mounted topivot about a bearing bolt 53 threaded into the carriage housing 42. Theopposite end of the lever 52 contains a cam follower 54 extendingthrough an opening in the plate 43 into the cam track 51. The camfollower may be a roller bearing or the like and is held captive in thecam tracks 51 functioning to move the arms 52 about the pivot 53 inresponse to linear movement of the shuttle 46. Quieter operation of theshuttle is achieved by driving the squeegee and flood bar from theshuttle 46 directly. An elongated slot 164 is formed in the shuttle 46(FIGS. 8-10) and a nylon roller 165 is positioned in the slot andsupported by the plate 43. Thus, the driving force is transmitteddirectly from the shuttle 46 to the plate 43, reducing noise andavoiding wear on the cam tracks 50 and 51 and their respectivefollowers.

The squeegee support lever 52 is provided with a squeegee assemblysupported by a threaded rod 61 bolted or attached to a flange 62 formedon the lower end of the support arm 52. A squeegee clamp 63 is carriedat the lower end of the threaded rod 61 to removably mount a squeegee 64of conventional design.

A second lever is pivotally mounted by a bearing bolt 71 fastened intothe squeegee support lever 52 and forms the support for the flood bar. Athreaded rod 73 is attached at one end to a flange 74 on the lower endof the lever 70, while the opposite end supports an L- shaped bracket 75for mounting a flood bar 76 of conventional design. A cam follower 77,identical to the cam follower 54 on the lever 52, is carried on the endof the lever 70 and extends through an opening in the plate 43 into thecam track 50. As is evident from the foregoing description,reciprocation of the shuttle 46 in a linear direction lifts the squeegeeand lowers the flood bar and vice versa with a scissors-type action.

The shuttle 46 is driven in its linear movement by a connecting rod 80joined at its opposite end to a drive arm 83 mounted on a main driveshaft (FIG. 6). A drive arm 82 of the same generally L-shapedconfiguration as the drive arm 83 is mounted for angular movement on theopposite end of the main drive shaft 85. As seen in FIGS. 1 and 2, thedrive arm 82 drives the shuttle of the carriage assembly 40 through adrive rod 84 identical to drive rod 80. While a drive rod is shown, itis contemplated that a cable, chain or other drive means may be used,depending on the final press configuration.

The press drive arrangement is best illustrated in FIGS. 4 and 6 andincludes a motor mounted on a movable motor support 101. A threadedshaft 106 cooperates with threads in the motor support and permitsadjustment of the motor 100 relative to the frame 1 1. Suitable guidesare provided to assure proper movement of the motor 100 during speedadjustment. If desired, a mechanical drive arrangement such as a chainor worm drive may be provided to permit adjustment of the press speed bythe operator while standing at the console.

A variable speed drive pulley 102 is mounted on the motor 100 andthrough a belt 103 drives a pulley 104 mounted on the input shaft 109 ofa reduction gear arrangement located in the housing 105. The reductiongear arrangement is of known type having an output shaft 106 disposed atright angles to the input shaft 109 and extending from opposite sides ofthe reduction gear housing 105. On one end of the output shaft 106 is amain drive arm 110 while on the opposite end is a press lift cam 108 anda plurality of cams 111, 112 and 113 which cooperate with switches 114,115 and 116. Cams 111-113 are angularly adjustable on the shaft 106 totime the actuation of the cooperating switches 1 14-1 16 to performvarious functions in the printing cycle, e.g., energize the vacuum bed,apply the blow-back and energize the vacuum take-off. Obviously,additional switches can be provided for any other accessories whichmight be added to the press. Timing of the switch operation is easilyadjusted because of the convenient location of the drive unit,permitting the relationship to the lifting cam 108 to be visuallyobserved.

The press drive arm 110 is connected through a second arm to an arm 121which is generally L- shaped, having the arm 122 joined to the shaft 85.The drive arm 121 is provided with an arcuate slot 123 which permits therod 122 to be angularly adjusted, thereby selecting the length of strokeof the press. The arm 120 moves through approximately 90, impartingmovement to the shaft 85 which, in turn, moves the arms 82 and 83 anddrives the carriage assemblies 40 and 41 in a manner to be describedmore fully in connection with the description of the operation of thepress.

As seen in FIG. 2, the press lift cam 108 cooperates with a followerwhich is rigidly connected by arm 131 to the brace 32 across the rear ofthe press arms 22 and 23. When the high side of the cam 108 is engagedwith the follower 130, the arm 131 is moved down, elevating the presshead to the condition shown in FIG. 1. When the low side of the cam 108engages the follower 130, the weight of the press head 20 causes it tobe lowered to the print position shown in FIGS. 2-4. The dwell of thepress in either condition is easily built into the cam design to permitit to remain a certain percentage of a full cycle in the elevated andlowered positions. The actual duration of dwell in any cycle may beadjusted by speeding up or slowing down the press through moving themotor 100 on the guides which automatically adjusts variable pulley 102and is limited only by the speed with which Stock to be printed can beplaced on the bed and removed after printing is complete.

As seen in FIGS. 2-4, the novel design of the drive for the presspermits it to be located within the sides of the bed 14 and chase 24(FIG. 3). This drive arrangement allows stroke length to be shortenedfrom the rear of the press toward the front assuring that no appreciablemovementof the squeegee will occur when the press head 20 is elevated.As best seen in FIG. 2, the bed 14 is unobstructed by the drive arms 82and 83 when the squeegee is in position to start the printing stroke.This arrangement permits mechanical feeds, conveyors and the like to beused with the press or the press used as an adjunct to an existingconveyor line.

As described briefly above, all of the drive elements are located at therear of the press to provide smooth operation, simplify the design,minimize cost, maximize ease of servicing and permit the press to bescaled up or down with no appreciable change in the press driverequired. In part, these advantages are attributable to mechanical drivearrangement as is best shown in FIG. 4. The axis about which the presshead pivots is coextensive with the geometric axis of the shaft 28. Thedrive arm axis is coextensive with the geometric axis of the shaft 85.These two axes are located in vertical alignment with the drive shaft ofthe gear box disposed below the upper axis and above the lower axis andthe axes forming a triangular pattern. The press stroke can be shortenedor lengthened by moving the end of the arm 120 in the slot 123 and thecarriage assemblies 40 and 41 will remain substantially fixed relativeto the arms 21 and 22 when the press head 20 is elevated. As is evident,movement of the carriage assemblies 40 and 41 relative to the arms 21and 22 when the press head is elevated is undesirable because of thepossible damage to the work through ink splatter, dropping, smearing orthe like.

The peeling arrangement can be seen in FIGS. 4 and 6 and is identifiedgenerally by references 140 and 141. The peeling arrangement isidentical on each side of the press and, therefore, specific descriptionwill b limited to that shown in FIG. 6.

A cable 142 is connected as at 143 to the master chase 24. Quicklyreleasable connections are provided to permit the press arms to beelevated independently of the chase, thereby facilitating screeninsertion and removal. In this condition, the squeegee and flood barsmay also be removed for cleaning and the like without affecting theiradjustment. The cable 142 extends over a pulley 144 which is housedwithin the front of the press arm 23 and through the press arm 23 andover a pulley 145 located at the rear of the press arm 23. The cableterminates at a turnbuckle assembly 146 after having been wrappedslightly more than 90 around the pulley 145.

The turnbuckle assembly is of known type andv is connected through anarm 147 to a collar 148 which is mounted for rotation with the shaft 85and serves to permit easy adjustment of the tension on the cable. Whenthe press is in the down position and the carriage assemblies 40 and 41are located at the initiation of the printing stroke, the collar I48 andconnecting link 147 are in the condition shown. As the shaft 85 rotatesin response to movement of the arm 110, a pulling force is exerted onthe cable, lifting the master chase 24 in opposition to the downwardpressure exerted by the squeegee 64 on the screen S.

The sequence of events is illustrated in FIGS. A, 5B and 5C,demonstrating the various conditions of peeling of the screen S in themaster chase 24 in schematic form with the degree of peel exaggerated.In FIG. 5A, the carriage assembly 41 has just commenced its rearwardmovement, at which time the elevation of the master chase 24 isprogressing at a fairly slow rate. As the carriage assembly 41approaches the mid-position shown in FIG. 5B, the master chase 24 isbeing elevated at a faster rate. As the squeegee approaches the rear orend of the print stroke, the master chase 24 assumes the generalcondition shown in FIG. 5C and the rate of elevation is decreasing.

The peeling function during off-contact printing is according toharmonic pattern which is graphically demonstrated in FIG. 11 where Arepresents the peeling curve of a known type of press with curve Brepresenting the curve of peeling of the press of the present invention.The ordinate of the graph is when screen lift or rise is plotted againstsqueegee movement for a full cycle. This is highly desirable because itis in the central region of the screen that the most stretch isexperienced regardless of the tension on the screen, while little or nostretch is experienced in the final stages of the print stroke.Moreover, the pressure can be kept quite uniform because the soleopposition to the elevating movement is provided by the flexibility ofthe squeegee. Accordingly, off-contact printing producing an excellentfinished product is possible through the present design.

If the operator does not desire off-contact printing, he can loosen thecables at their rearward ends by the tum-buckles provided with verylittle effort. It is to be appreciated that off-contact printing may notbe necessary when the screen material does not have any appreciablestretch and, thus, the peeling function would become unnecessary.Stainless steel fabrics and the like would fall in the little or nostretch category. It should be noted that the cables for the peelingmeans are located within the press arms where they are free frominterference with the press operation.

The conversion from flood to non-flood scoop is quickly accomplished bythe novel design of the carriage assembly of the present invention. Thescissors arrangement formed by the levers 52 and supporting the squeegeeand floor bar assemblies, respectively, shifts in the manner shown inFIGS. 8 and 9 on the print and flood strokes, respectively. On the floodstroke, as shown in FIG. 9, the pool of ink is pushed across the screenS on the return stroke while the screen is in the elevated conditionshown in FIG. 1. If it becomes desirable to convert to a non-flood scoopbecause of printing requirements, the cables are disconnected from thechase 24 and the press arms raised as shown in FIG. 1. The flood barclamp is then released and a non-flood scoop of the type indicated at727 in FIG. 10 is attached. The pivot pin or bearing bolt 71 is movedfrom the opening to the opening 131, passing through the same opening inthe lever 52. Effectively, this shortens the length of the flood barlever 70 and locates the scoop 79 to cooperate with the squeegee asshown on the return stroke. A similar change-over on the carriageassembly 40 is effected, the press head lowered, the cables reconnectedto the chase 24 and the press is now ready for non-flood printing.

In printing fabrics and the like, the flood bar or scoop 79 may bereplaced with a second squeegee to permit printing in both directions.In such event, the cam 108 will be timed to lower the press head 20before the movement of the carriage is commenced. As noted above, thequick release of the chase 24 from the cable ends permits the operatorto have access to the screen and squeegee and flood bars.

From the foregoing, it can be appreciated that conversion of the pressfrom flood to non-flood for off-contact printing can be rapidlyaccomplished with little effort and no special skill required. Thesimplicity of the mechanism assures proper non-flood and floodfunctioning at all times, as the scissors action of the levers 52 and 70is automatically actuated at every change in direction of the press.With the chase 24 in the down position and press head elevated, thesqueegee and flood bar areeasily removed, cleaned or replaced.

The operation of the press will now be described. When the press is inthe condition shown in FIG. 1, stock to be printed may be placed on thebed 14. A start button on the operating console 12 is actuated,energizing the motor 100 and causing the shaft to rotate. Through themain press drive linkage, the drive arms 82 and 83 are moved to theforward position to bring the carriage assemblies 40 and 41 to the frontof the press. The condition of each carriage assembly during the forwardor non-print stroke is illustrated in FIG. 9 for the flood-typeoperation while FIG. illustrates the condition assumed if a non-floodscoop is used. In either event, the'ink pool is moved to the front ofthe screen.

As the shaft 106 continues its rotation, the direction of the main drivearms 82 and 83 reverses, causing the shuttle mechanism in each of therespective carriage assemblies 40 and 41 to reverse, elevating the floodbar and lowering the squeegee into engagement with the screen S, suchcondition being illustrated in FIG. 8 and schematicallY in FIG. 5A. Justbefore the arms 82 and 83 reverse direction, the press lift cam 108reaches its low side and the press head is lowered to the conditionshown in FlG..2. As the direction of the drive arms 82 and 83 isreversed, the shuttle mechanisms are shifted to the condition Shown inFIGS. 8 and 5A which is illustrative of the initiation of the printstroke. The main drive arms 82 and 83 continue to be rotated by theshaft 85 in a rearward direction to pull the squeegee across the screenS. In off-contact printing, as the shaft 85 moves, the peeling mechanismfunctions in the sequence shown in FIGS. 5A, 5B and 5C.- In oncontactprinting, no elevation of the screen is ex perienced.

When the main drive arms 82 and 83 reach the condition shown in dottedlines for the arm 83 in FIG. 4, the respective carriage assemblies 40and 41 are at the rear of the respective press arms 22 and 23. At thistime, the press lift cam 108 approaches the high side or rise conditionto elevate the arms 22 and 23, elevating the press head 20 to thecondition shown in FIG. 1. The press will either dwell or stop in thiscondition, depending On the mode of operation selected. The desired modeof operation can be selected at the console 12, enabling the press to beoperated at single stroke or continuously with a period of dwell at theelevated condition to permit removal of the printed stock and insertionof the unprinted stock. Single-cycle manual operation is also possible.

From the foregoing, it can been seen that the drive for the squeegee isdirectly From the arms and shifting of the squeegee and flood bar issimultaneous with the reversal of stroke, regardless of stroke length,and thereby eliminating the need for stops or the like with theundesirable noise and adjustment problems. The present design of presspermits the stroke length to be shortened or lengthened from the frontto back with one simple adjustment of the end of the arm 120 in theangular slot 123. This is made possible since the reversal of directionautomatically actuates the shuttle mechanisms to shift the squeegee andflood bar rather than fixed stops of the prior art. Moreover, the novelsqueegee and flood bar arrangement permits the rapid conversion fromflood to non-flood scoop with a minimum of effort and without requiringexcessive cost in press construction.

It is to be appreciated that the press of the present invention throughits novel features is of rugged design which is quite economical tomanufacture. Moreover, the press is of universal design, permitting itto be scaled up or down to meet particular customer requirements. Theadjustments provided give great flexibility in its use.

Upon a consideration of the foregoing, it will become obvious to thoseskilled in the art that various modifications may be made withoutdeparting from the invention embodied herein. Therefore, only suchlimitations should be imposed as are indicated by the spirit and scopeof the appended claims.

We claim:

1. In a screen-type printing press wherein a stencil screen is heldagainst a surface to be printed and a squeegee is moved across saidscreen from front to back to force ink therethrough onto said surface tobe printed, the improvement comprising peeling means connected to saidstencil screen for elevating said stencil screen from said surface to beprinted after said squeegee has passed over said screen, and to elevatesaid screen at a faster rate when said squeegee is centrally of saidstencil screen than when said squeegee is at either said front or backof saId stencil screen.

2. The improvement in screen-type printing presses as defined in claim 1wherein said peeling means is attached to a drive means, said drivemeans being operatively connected to said squeegee for moving saidsqueegee from front to back.

3. The improvement in screen-type printing presses as defined in claim 1wherein said peeling means is substantially opposed in its elevatingmovement solely by the downward force exerted by said squeegee on saidscreen.

4. The improvement in screen-type printing presses as defined in claim 2wherein said drive means for moving said squeegee from front to backincludes a carriage assembly, lever means mounting said squeegee and aflood bar on said carriage assembly, shuttle means in cluding a pair ofcam tracks engaged by cam follower means on said lever means, saidshuttle means thereby shifting said lever means, to shift said squeegeeand said flood bar relative to each other, said shuttle means beingconnected to said drive means such that said shifting of said squeegeeand said flood bar will automatically occur on change of direction ofsaid drive means.

5. The improvement in screentype printing presses as defined in claim 4wherein means is provided in said drive means to shorten the length ofthe print stroke as measured from the front of the press.

6. A printing press having a frame, a bed supported on said frame andhaving an upwardly facing surface to receive work to be printed, a pairof spaced-apart arms mounted for pivoting movement toward and away fromsaid bed, a screen removably mounted on a chase, said chase beingmounted for pivoting movement beneath said arms to facilitatereplacement of said screen and to allow movement of said chase withrespect to said arms during off-contact printing and adapted forpositioning over said work on said bed, a carriage assembly mounted oneach of said arms, drive means on said frame connected to said carriageassemblies to move said carriage assemblies from a rear portion of saidarms to a forward portion of said arms and return, each of said carriageassemblies including a carriage housing supported on each of said arms,a squeegee and flood bar mounted on said carriage assemblies by means oneach of said carriage housings for supporting an end of said squeegeeand flood bar for pivoting movement relative to each other in timedrelation to said positioning of said screen over said bed on said chase,said squeegee being brought into contact with said screen when saidscreen is in engagement with said work by said means supporting saidsqueegee and flood bar, said means shifting said squeegee and flood barrelative to each other to automatically and properly position the sameduring movement on said arms.

7. The printing press of claim 6 wherein said printing press is providedwith registration means mounted thereon for locating said forwardportion of said arms relative to said bed.

8. The printing press of claim 7 wherein said chase is provided withguide means at a forward end thereof to maintain registration as saidchase is lifted from said bed relative to said arms to accomplishoff-contact printing.

9. The printing press of claim 6 wherein said means for shifting saidsqueegee and flood bar includes first and second levers, said firstlever being mounted on I said housing for pivoting movement relativethereto, said second lever being mounted directly on said first leverfor pivoting movement relative to and indepen dent of said first leverand said housing, and clamp means on the end of said levers forsupporting said squeegee and flood bar.

10. A printing press having a frame, a bed supported on said framehaving an upwardly facing surface to receive work to be printed, a pairof spaced-apart arms mounted for pivoting movement toward and away fromsaid bed, a screen removably mounted on a chase, said chase beingmounted for pivoting movement beneath said arms and adapted forpositioning over said work on said bed, a carriage assembly mounted oneach of said arms, drive means on said frame connected to said carriageassemblies to move said carriage assemblies from a rear portion of saidarms to a forward portion of said arms and return, each of said carriageassemblies including a carriage housing supported on each of said arms,a squeegee and flood bar mounted on said carriage assemblies by means oneach of said carriage housings for supporting .an end of said squeegeeand flood bar for pivoting movement relative to each other in timedrelation to said positioning of said screen over said bed on said chase,said squeegee being brought into contact with said screen when saidscreen in is engagement with said work by said means supporting saidsqueegee and flood bar, said means shifting said squeegee and flood barrelative to each other to automatically and properly position the sameduring movement on said arms and including first and second levers, saidfirst lever being mounted on said housing for pivoting movement relativethereto, said second lever being mounted directly on said first leverfor pivoting movement relative to and independent of said first leverand said housing, and clamp means on the end of said levers forsupporting said squeegee and flood bar, and a shuttle havingoppositely-directed cam tracks therein, and cam follower means on eachof said first and second levers cooperating with saidoppositely-directed earn tracks in said shuttle, whereby movement ofsaid shuttle causing shifting of said squeegee and flood bar.

H. A printing press having a frame, a bed supported on said frame havingan upwardly facing surface to receive work to be printed, a pair ofspaced-apart arms mounted for pivoting movement toward and away fromsaid bed, a screen removably mounted on a chase, said chase beingmounted for pivoting movement beneath said arms and adapted forpositioning over said work said bed, a carriage assembly mounted on eachof said arms, drive means on said frame connected to said carriageassemblies to move said carriage assemblies from a rear portion of saidarms to a forward portion of said arms and return, each of said carriageassemblies including a carriage housing supported on each of said arms,a squeegee and flood bar mounted on said carriage assemblies by means oneach of said' carriage housings for supporting an end of said squeegeeand flood bar for pivoting movement relative to each other in timedrelation to said positioning of said screen over said bed on said chase,said squeegee being brought into contact with said screen when saidscreen is in engagement with said work by said means supporting saidsqueegee and flood bar, said means shifting said squeegee and flood barrelative to each other to automatically and properly position the sameduring movement on said arms and including first and second levers, saidfirst lever being mounted on said housing for pivoting movement relativethereto, said second lever being mounted directly on said first leverfor pivoting movement relative to and independent of said first leverand said housing, and clamp means on the end of said levers forsupporting said squeegee and flood bar, and having means on one of saidlevers to permit the pivot for the other of said levers to be movedrelative to said one lever to convert said carriage to a non-flood scoopprinting operation.

12. The printing press of claim 6 wherein said drive means mounted onsaid frame includes a drive arm disposed outside each of said armssupporting said carriage assemblies, to permit scaling in size of saidpress, each of said drive arms being joined to said means for shiftingsaid squeegee and flood bar relative to each other.

13. A'printing press having a frame, a bed supported on said frame andhaving an upwardly facing surface to receive work to be printed, a pairof spaced-apart support arms mounted on said frame for pivoting movementtoward and away from said bed, a screen removably mounted on a chase,said chase being mounted for pivoting movement beneath said support armsand adapted for positioning over said work on said bed, a carriageassembly mounted on each of said support arms, drive means mounted onsaid frame and connected to said carriage assemblies for reciprocatingeach of said carriage assemblies from a rear portion of each of saidsupport arms to a forward portion thereof and return, said drive meansbeing disposed within the side margins of said chase and including apair of rigid L-shaped arms movable abouta common axis for shifting saidcarriage assemblies on said support arms, said support arms beingdisposed on an axis which is in substantial vertical alignment with saidaxis of said L- shaped arms to facilitate adjustment of the length ofthe print stroke and to reduce the size of the press and the spacerequired for its operation.

14. The printing press of claim 13 wherein said drive means includes apower drive shaft, adjustable linkage means to impart motion from saidpower drive shaft to said L-shaped arms, said power drive shaft beingdisposed on an axis below said axis of said support arms and above theaxis of said drive means, thereby to permit adjustment of the length ofstroke of said carriage.

15. A printing press as defined in claim 13 wherein each of saidcarriage assemblies includes a carriage housing supported on each ofsaid arms, a squeegee and a flood bar mounted on said carriageassemblies by means on each of said carriage housings for supporting anend of said squeegee and flood bar for pivoting movement relative toeach other in timed relation to movement of said screen over said bed,said means on said carriage housing being responsive to changes indirection of said L-shaped arms to shift said squeegee and flood barrelative to each other, thereby to automatically and properly positionthe same during movement on said arms.

16. A printing press having a frame, a bed supported on said framehaving an upwardly facing surface to receive work to be printed, a pairof spaced-apart support arms mounted on said frame for pivoting movementtoward and away from said bed, a screen removably mounted on a chase,said chase being mounted for pivoting movement beneath said support armsand adapted for positioning over said work on said bed, a carriageassembly mounted on each-of said support arms, each of said carriageassemblies including a carriage housing supported on each of said arms,

a squeegee and a flood bar mounted on said carriage assemblies by meanson each of said carriagehousings for supporting an end of said squeegeeand flood bar for pivoting movement relative to each other in timedrelation to movement of said screen over said bed, drive means mountedon said frame connected to said carriage assemblies for reciprocatingeach of said carriage assemblies from a rear portion each of saidsupport arms to a forward portion of each of said support arms andreturn, said drive means being disposed within the side margins of saidchase and including a pair of rigid L-shaped arms movable about a commonaxis for shifting said carriage assemblies on said support arms, saidmeans on said carriage housings being responsive to changes in directionof said L-shaped arms to shift said squeegee and flood bar relative toeach other thereby to automatically and properly position the sameduring movement on said arms, each of said carriage assemblies includingbrake means to assure shifting of said squeegee and flood bar onreversal of direction of said carriage movement.

17. The printing press of claim 15 wherein said means for shifting saidsqueegee and flood bar includes first and second levers, said firstlever being mounted on said housing for pivoting movement relativethereto, said second lever being mounted directly on said first leverfor pivoting movement relative to and independent of said first leverand said housing, and clamp means on the end of said levers forsupporting said squeegee and flood bar.

.a squeegee and a flood bar mounted on said carriage assemblies by meanson each of said carriage housings for supporting an end of said squeegeeand flood bar for pivoting movement relative to each other in timedrelation to movement of said screen over said bed, said means includingfirst and second levers, said first lever being mounted on said housingfor pivoting movement relative thereto, said second lever being mounteddirectly on said first lever for pivoting movement rela tive to andindependent of said first lever and said housing, and clamp means on theend of said levers for supporting said squeegee and flood bar, saidmeans shiftin g said squeegee and flood bar also including a shuttlehaving oppositely-directed cam tracks therein, and cam follower means oneach of said first and second levers cooperating with saidoppositely-directed cam tracks in said shuttle, whereby movement of saidshuttle causes shifting of said squeegee and flood bar, and drive meansmounted on said frame connected to said carriage assemblies forreciprocating each of said carriage assemblies from a rear portion ofeach of said support arms to a forward portion of each of said supportarms and return, said drive means being disposed within the side marginsof said chase and including a pair of rigid L-shaped arms movable abouta common axis for shifting said carriage assemblies on said supportarms, said means on said carriage housings being responsive to changesin direction of said L-shaped arms to shift said squeegee and flood barrelative to each other thereby to automatically and properly positionthe same during movement of said arms.

19. A printing press having a frame, a bed supported on said framehaving an upwardly facing surface to receive work to be printed, a pairof spaced-apart support arms mounted on said frame for pivoting movementtward and away from said bed, a screen removably mounted on a chase,said chase being mounted for pivoting movement beneath said support armsand adapted for positioning over said work on said bed, a carriageassembly mounted on each of said support arms, each of said carriageassemblies including a carriage housing supported on each of said arms,a squeegee and a flood bar mounted on said carriage assemblies by meanson each of said carriage housings for supporting an end of said squeegeeand flood bar for pivoting movement relative to each other in timedrelation to movement of said screen over said bed, said means includingfirst and second levers, said first lever being mounted on said housingfor pivoting movement relative thereto, said second lever being mounteddirectly on said first lever for pivoting movement relative to andindependent of said first lever and said housing, and clamp means on theend of said levers for supporting said squeegee and flood bar, andincluding means on one of said levers to permit the pivot for the otherof said levers to be moved relative to said one lever to convert saidcarriage to a non-flood scoop printing operation, and drive meansmounted on said frame connected to said carriage assemblies forreciprocating each of said carriage assemblies from a rear portion ofeach of said support arms to a forward portion of each of said supportarms and return, said drive means being disposed within the side marginsof said chase and including a pair of rigid L-shaped arms movable abouta common axis for shifting said carriage assemblies on said supportarms, said means on said

1. In a screen-type printing press wherein a stencil screen is heldagainst a surface to be printed and a squeegee is moved across saidscreen from front to back to force ink therethrough onto said surface tobe printed, the improvement comprising peeling means connected to saidstencil screen for elevating said stencil screen from said surface to beprinted after said squeegee has passed over said screen, and to elevatesaid screen at a faster rate when said squeegee is centrally of saidstencil screen than when said squeegee is at either said front or backof saId stencil screen.
 2. The improvement in screen-type printingpresses as defined in claim 1 wherein said peeling means is attached toa drive means, said drive means being operatively connected to saidsqueegee for moving said squeegee from front to back.
 3. The improvementin screen-type printing presses as defined in claim 1 wherein saidpeeling means is substantially opposed in its elevating movement solelyby the downward force exerted by said squeegee on said screen.
 4. Theimprovement in screen-type printing presses as defined in claim 2wherein said drive means for moving said squeegee from front to backincludes a carriage assembly, lever means mounting said squeegee and aflood bar on said carriage assembly, shuttle means including a pair ofcam tracks engaged by cam follower means on said lever means, saidshuttle means thereby shifting said lever means, to shift said squeegeeand said flood bar relative to each other, said shuttle means beingconnected to said drive means such that said shifting of said squeegeeand said flood bar will automatically occur on change of direction ofsaid drive means.
 5. The improvement in screen-type printing presses asdefined in claim 4 wherein means is provided in said drive means toshorten the length of the print stroke as measured from the front of thepress.
 6. A printing press having a frame, a bed supported on said frameand having an upwardly facing surface to receive work to be printed, apair of spaced-apart arms mounted for pivoting movement toward and awayfrom said bed, a screen removably mounted on a chase, said chase beingmounted for pivoting movement beneath said arms to facilitatereplacement of said screen and to allow movement of said chase withrespect to said arms during off-contact printing and adapted forpositioning over said work on said bed, a carriage assembly mounted oneach of said arms, drive means on said frame connected to said carriageassemblies to move said carriage assemblies from a rear portion of saidarms to a forward portion of said arms and return, each of said carriageassemblies including a carriage housing supported on each of said arms,a squeegee and flood bar mounted on said carriage assemblies by means oneach of said carriage housings for supporting an end of said squeegeeand flood bar for pivoting movement relative to each other in timedrelation to said positioning of said screen over said bEd on said chase,said squeegee being brought into contact with said screen when saidscreen is in engagement with said work by said means supporting saidsqueegee and flood bar, said means shifting said squeegee and flood barrelative to each other to automatically and properly position the sameduring movement on said arms.
 7. The printing press of claim 6 whereinsaid printing press is provided with registration means mounted thereonfor locating said forward portion of said arms relative to said bed. 8.The printing press of claim 7 wherein said chase is provided with guidemeans at a forward end thereof to maintain registration as said chase islifted from said bed relative to said arms to accomplish off-contactprinting.
 9. The printing press of claim 6 wherein said means forshifting said squeegee and flood bar includes first and second levers,said first lever being mounted on said housing for pivoting movementrelative thereto, said second lever being mounted directly on said firstlever for pivoting movement relative to and independent of said firstlever and said housing, and clamp means on the end of said levers forsupporting said squeegee and flood bar.
 10. A printing press having aframe, a bed supported on said frame having an upwardly facing surfaceto receive work to be printed, a pair of spaced-apart arms mounted forpivoting movement toward and away from said bed, a screen removablymounted on a chase, said chase being mounted for pivoting movementbeneath said arms and adapted for positioning over said work on saidbed, a carriage assembly mounted on each of said arms, drive means onsaid frame connected to said carriage assemblies to move said carriageassemblies from a rear portion of said arms to a forward portion of saidarms and return, each of said carriage assemblies including a carriagehousing supported on each of said arms, a squeegee and flood bar mountedon said carriage assemblies by means on each of said carriage housingsfor supporting an end of said squeegee and flood bar for pivotingmovement relative to each other in timed relation to said positioning ofsaid screen over said bed on said chase, said squeegee being broughtinto contact with said screen when said screen in is engagement withsaid work by said means supporting said squeegee and flood bar, saidmeans shifting said squeegee and flood bar relative to each other toautomatically and properly position the same during movement on saidarms and including first and second levers, said first lever beingmounted on said housing for pivoting movement relative thereto, saidsecond lever being mounted directly on said first lever for pivotingmovement relative to and independent of said first lever and saidhousing, and clamp means on the end of said levers for supporting saidsqueegee and flood bar, and a shuttle having oppositely-directed camtracks therein, and cam follower means on each of said first and secondlevers cooperating with said oppositely-directed cam tracks in saidshuttle, whereby movement of said shuttle causing shifting of saidsqueegee and flood bar.
 11. A printing press having a frame, a bedsupported on said frame having an upwardly facing surface to receivework to be printed, a pair of spaced-apart arms mounted for pivotingmovement toward and away from said bed, a screen removably mounted on achase, said chase being mounted for pivoting movement beneath said armsand adapted for positioning over said work said bed, a carriage assemblymounted on each of said arms, drive means on said frame connected tosaid carriage assemblies to move said carriage assemblies from a rearportion of said arms to a forward portion of said arms and return, eachof said carriage assemblies including a carriage housing supported oneach of said arms, a squeegee and flood bar mounted on said carriageassemblies by means on each of said carriage housings for supporting anend of said squeegee and flood bar for pivoting movement relative toeach other in timed rElation to said positioning of said screen oversaid bed on said chase, said squeegee being brought into contact withsaid screen when said screen is in engagement with said work by saidmeans supporting said squeegee and flood bar, said means shifting saidsqueegee and flood bar relative to each other to automatically andproperly position the same during movement on said arms and includingfirst and second levers, said first lever being mounted on said housingfor pivoting movement relative thereto, said second lever being mounteddirectly on said first lever for pivoting movement relative to andindependent of said first lever and said housing, and clamp means on theend of said levers for supporting said squeegee and flood bar, andhaving means on one of said levers to permit the pivot for the other ofsaid levers to be moved relative to said one lever to convert saidcarriage to a non-flood scoop printing operation.
 12. The printing pressof claim 6 wherein said drive means mounted on said frame includes adrive arm disposed outside each of said arms supporting said carriageassemblies, to permit scaling in size of said press, each of said drivearms being joined to said means for shifting said squeegee and flood barrelative to each other.
 13. A printing press having a frame, a bedsupported on said frame and having an upwardly facing surface to receivework to be printed, a pair of spaced-apart support arms mounted on saidframe for pivoting movement toward and away from said bed, a screenremovably mounted on a chase, said chase being mounted for pivotingmovement beneath said support arms and adapted for positioning over saidwork on said bed, a carriage assembly mounted on each of said supportarms, drive means mounted on said frame and connected to said carriageassemblies for reciprocating each of said carriage assemblies from arear portion of each of said support arms to a forward portion thereofand return, said drive means being disposed within the side margins ofsaid chase and including a pair of rigid L-shaped arms movable about acommon axis for shifting said carriage assemblies on said support arms,said support arms being disposed on an axis which is in substantialvertical alignment with said axis of said L-shaped arms to facilitateadjustment of the length of the print stroke and to reduce the size ofthe press and the space required for its operation.
 14. The printingpress of claim 13 wherein said drive means includes a power drive shaft,adjustable linkage means to impart motion from said power drive shaft tosaid L-shaped arms, said power drive shaft being disposed on an axisbelow said axis of said support arms and above the axis of said drivemeans, thereby to permit adjustment of the length of stroke of saidcarriage.
 15. A printing press as defined in claim 13 wherein each ofsaid carriage assemblies includes a carriage housing supported on eachof said arms, a squeegee and a flood bar mounted on said carriageassemblies by means on each of said carriage housings for supporting anend of said squeegee and flood bar for pivoting movement relative toeach other in timed relation to movement of said screen over said bed,said means on said carriage housing being responsive to changes indirection of said L-shaped arms to shift said squeegee and flood barrelative to each other, thereby to automatically and properly positionthe same during movement on said arms.
 16. A printing press having aframe, a bed supported on said frame having an upwardly facing surfaceto receive work to be printed, a pair of spaced-apart support armsmounted on said frame for pivoting movement toward and away from saidbed, a screen removably mounted on a chase, said chase being mounted forpivoting movement beneath said support arms and adapted for positioningover said work on said bed, a carriage assembly mounted on each of saidsupport arms, each of said carriage assemblies including a carriagehousing supported on each of said arms, a squeegeE and a flood barmounted on said carriage assemblies by means on each of said carriagehousings for supporting an end of said squeegee and flood bar forpivoting movement relative to each other in timed relation to movementof said screen over said bed, drive means mounted on said frameconnected to said carriage assemblies for reciprocating each of saidcarriage assemblies from a rear portion each of said support arms to aforward portion of each of said support arms and return, said drivemeans being disposed within the side margins of said chase and includinga pair of rigid L-shaped arms movable about a common axis for shiftingsaid carriage assemblies on said support arms, said means on saidcarriage housings being responsive to changes in direction of saidL-shaped arms to shift said squeegee and flood bar relative to eachother thereby to automatically and properly position the same duringmovement on said arms, each of said carriage assemblies including brakemeans to assure shifting of said squeegee and flood bar on reversal ofdirection of said carriage movement.
 17. The printing press of claim 15wherein said means for shifting said squeegee and flood bar includesfirst and second levers, said first lever being mounted on said housingfor pivoting movement relative thereto, said second lever being mounteddirectly on said first lever for pivoting movement relative to andindependent of said first lever and said housing, and clamp means on theend of said levers for supporting said squeegee and flood bar.
 18. Aprinting press having a frame, a bed supported on said frame having anupwardly facing surface to receive work to be printed, a pair ofspaced-apart support arms mounted on said frame for pivoting movementtoward and away from said bed, a screen removably mounted on a chase,said chase being mounted for pivoting movement beneath said support armsand adapted for positioning over said work on said bed, a carriageassembly mounted on each of said support arms, each of said carriageassemblies including a carriage housing supported on each of said arms,a squeegee and a flood bar mounted on said carriage assemblies by meanson each of said carriage housings for supporting an end of said squeegeeand flood bar for pivoting movement relative to each other in timedrelation to movement of said screen over said bed, said means includingfirst and second levers, said first lever being mounted on said housingfor pivoting movement relative thereto, said second lever being mounteddirectly on said first lever for pivoting movement relative to andindependent of said first lever and said housing, and clamp means on theend of said levers for supporting said squeegee and flood bar, saidmeans shifting said squeegee and flood bar also including a shuttlehaving oppositely-directed cam tracks therein, and cam follower means oneach of said first and second levers cooperating with saidoppositely-directed cam tracks in said shuttle, whereby movement of saidshuttle causes shifting of said squeegee and flood bar, and drive meansmounted on said frame connected to said carriage assemblies forreciprocating each of said carriage assemblies from a rear portion ofeach of said support arms to a forward portion of each of said supportarms and return, said drive means being disposed within the side marginsof said chase and including a pair of rigid L-shaped arms movable abouta common axis for shifting said carriage assemblies on said supportarms, said means on said carriage housings being responsive to changesin direction of said L-shaped arms to shift said squeegee and flood barrelative to each other thereby to automatically and properly positionthe same during movement of said arms.
 19. A printing press having aframe, a bed supported on said frame having an upwardly facing surfaceto receive work to be printed, a pair of spaced-apart support armsmounted on said frame for pivoting movement toward and away from saidbed, a screen removably mounted on a Chase, said chase being mounted forpivoting movement beneath said support arms and adapted for positioningover said work on said bed, a carriage assembly mounted on each of saidsupport arms, each of said carriage assemblies including a carriagehousing supported on each of said arms, a squeegee and a flood barmounted on said carriage assemblies by means on each of said carriagehousings for supporting an end of said squeegee and flood bar forpivoting movement relative to each other in timed relation to movementof said screen over said bed, said means including first and secondlevers, said first lever being mounted on said housing for pivotingmovement relative thereto, said second lever being mounted directly onsaid first lever for pivoting movement relative to and independent ofsaid first lever and said housing, and clamp means on the end of saidlevers for supporting said squeegee and flood bar, and including meanson one of said levers to permit the pivot for the other of said leversto be moved relative to said one lever to convert said carriage to anon-flood scoop printing operation, and drive means mounted on saidframe connected to said carriage assemblies for reciprocating each ofsaid carriage assemblies from a rear portion of each of said supportarms to a forward portion of each of said support arms and return, saiddrive means being disposed within the side margins of said chase andincluding a pair of rigid L-shaped arms movable about a common axis forshifting said carriage assemblies on said support arms, said means onsaid carriage housings being responsive to changes in direction of saidL-shaped arms to shift said squeegee and flood bar relative to eachother thereby to automatically and properly position the same duringmovement on said arms.
 20. The printing press of claim 18 wherein saidL-shaped drive arms are disposed outside each of said arms supportingsaid carriage assemblies and each of said L-shaped drive arms has meansfor joining it to said shuttle for shifting said squeegee and flood barrelative to each other.